XII Physics Solved Numericals | Ch# 15 Molecular Theory of Gases

Board: Sindh Boards Class : 12, Second Year Subject: Physics Unit #15 Molecular Theory of Gases Numericals: 15.1. The freezing point of mercury is —39°C.Convert it into °F and the comfort level temperature of 20° into Kelvin. (Ans: —38.2°F, 293K) 15.2. The boiling point of liquid nitrogen is -321°F. Change it into equivalent Kelvin temperature. (Ans: 77K) 15.3. Calculate the volume occupied by a gram-mole of a gas at 0°C and a pressure of 1.0 atmosphere. (Ans: 22.4 liters/mole) 15.4. An air storage tank whose volume is 112 liters contain 3kg of air at a pressure of 18 atmospheres. How much air would have to be forced into the tank to increase the pressure to 21 atmospheres, assuming no change in temperature? (Ans: 0.5kg) 15.5. A balloon contains 0.04m3 of air at a pressure of 120KPa. Calculate the pressure required to reduce its volume to 0.025 m3 at constant temperature. (Ans: 1.9 x 105Pa) 15.6. The molar mass of nitrogen gas N2 is 28gmor'. For 100g of nitrogen, calculate. (a) the number of moles. (Ans: (a) 3.57 mole) (b) the volume occupied at room temperature (20°C) and pressure of 1.01 x 105 Pa. (Ans: (b) 0.086m3 or 86dm3) 15.7. A sample of a gas contains 3.0 x 1024 atoms. Calculate the volume of the gas at a temperature of 300K and a pressure of 120K Pa. (Ans: 0.104m3) 15.8. Calculate the root mean square speed of hydrogen molecules at 0°C and 1.0 atm pressure. Assuming hydrogen to be an ideal gas. The density of hydrogen is 8.99 x10-2 kg/m3. (Ans: 1835.86ms-I) 15.9. Calculate the root mean square speed of hydrogen molecule at 500K (mass of proton = 1.67 x 10-27kg and K = 1.38 x 10-23J/molecule.-K) (Ans: 2489.49ms-I) 15.10. (a) Determine the average value of the Kinetic energy of the particles of an ideal gas at 10°C and at 40°C. (Ans: 5.86x10-2IJ, 6.48x10-21.1) (b) What is the Kinetic energy per mole of an ideal gas at thesetemperatures? (Ans: 3526.57J, 3901J)